Inhomogeneity in the drying process of gelatin film formation: NMR microscopy and relaxation study

Gelatin film formation was investigated in situ during evaporation of the solvent. Gelatin was dissolved in deuterium oxide (D2O) at 50 degrees C followed by casting. The drying process of the gelatin-D2O solution system was observed using a single-sided NMR scanner by application of the Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence at different layer positions. The echo decays were analysed and spin-spin relaxation times (T-2) were obtained for each layer. It was found that the drying process for the film formation occurs in a stratified fashion. (C) 2009 Published by Elsevier B.V.